Why do we need protection?Electrical apparatus operates at various voltagelevels and may be enclosed or placed in open.Under abnormal operating conditions protection isnecessary for Safety of electrical equipments. Safety of human personnel
Construction :•There are two chambers in a low oil circuitbreaker,the oil in each chamber is separated fromeach other.•The main advantage of this is that low oil is requiredand oil in second chamber wont get polluted.•Upper chamber is called the circuit breakerchamber and lower one is called the supportingchamber.
Construction (Cont…) :•Circuit breaking chamber consists of moving contact and fixed contact. Moving contact is connected with a piston its just for the movement of the contact and no pressure build due to its motion.•There are two vents on fixed contact they are axial vent for small current produced in oil due to heating of arc and radial vents for large currents.•The whole device is covered using Bakelite paper and porcelain for protection. Vents are placed in a turbulator.